Automatic spark-timer for internal-combustion engines.



G. R. WRIGHT & F. W. JOHNSON.

AUTOMATIC SPARK TIMER FOR INTERNAL COMBUSTION ENGINES.

APPLICATION FILED MAR. 28, 1914.

Patented Sept. 8, 1914.

part section at one contact.

UNITED sTA'r s PATENT OFFICE.

GEORGE E. WRIGHT ANDFREDRICK W. JOHNSON, OF SARDIS, BRITISH COLUMBIA, CANADA.

AUTOMATIC SPARK-TIMER FOR INTERNAL-COMBUSTION ENGINES.

Specification of Letters Patent.

Patented Sept. 8, 1914.

Application filed March 28. 1914. Serial No. 828,073.

To all whom it may concern Be it known that we, Gnonon R. \VRIGHT and FREDRICK \V. JOHNSON, citizens of the Dominion of Canada, residing at Sardis, in the Province of British. Columbia, Canada, have invented certain new and us ul Improvements in Automatic Spark-Tuners for Internal-Combustion Engines, of which the following is a specification.

This invention relates to a spark timer for an internal combustion engine and is designed to automatically retard or advance the ignition spark as the speed of rotation of the engine varies.

In engines of this class, where such variation of speed is required, such as in the en gine of an automobile, it is desirable that provision be made for advancii'ig or retarding the time of ignition the speed of the engine varies; so that the full force of the explosion may be exerted on the piston when the crank pin is in a favorable position to rotate the crank shaft.

Means is usually provided in automobile engines for manually advancing or retarding the spark, but it is desirable that it be done automatically by the speed variation otherwise thefull advantage will not be derived.

The device, which is the subject of this application, has been designed whereby a change in the speed of rotation of the engine directly controls by centrifugal force the angular position of the sparking contact of each cylinder in relation to the position of its crank pin.

The invention is part icularlydescribed in the following specification, reference being made to the drawings by which it is accompanied, in which:

Figure 1 is an end view of the timer with Fig. 2 is a sectional plan of the same on the axis of the shaft. Fig. 3 is a perspective view of one of the variable contact members detached, and Fig. 1 is an enlarged detail showing the .contour of the contact surface.

Secured on the end of the cam shaft 2 of the engine, or on anyzshaft coiiperative with the engine which is rotatable at the same speedas the valve operating shaft. is a sleeve 3 having a flange 4 projecting from its inner end. to which flange is secured a hollow cylinder of insulating material such as fiber. Bearing on the outer side of this cylinder 5 is a multiple brush consisting of a series of separate brushes 6, one for each cylinder ot the engine, which are securedtogether. in one brush holder 7 of insulating material, each brush fibeing suit ably insulated from the others and separately connected at 8 to the ignition circuit of its cylinder. This multiple brush holder 8 is secured. on the end of a fiat spring 9 which is adjust-ably secured in a post 10 projecting from some adjacent part of the engine frame. The resilience of the spring 9 will thus hold the ends of the brushes into frictional contact with the cylinder 5 and they are collectively adjustable circumferentially to enable the time of ignition to be approxin'iately-adjusted to the angular p0- sition of the cranks.

Under the path of each brush 6 on the cylinder 5 a contact member 17 18, for each cylinder of the engine, is pivotally mounted on a pin 15 in an aperture 16 through the cylinder 5, which contacts are circumferentially longated, as at 17, backward from the pivots 15 in the directionof rotation of the cylinder 5, to insure an effective closure of the ignition circuit.

Forward from the pivot 15 the contact member is circumferentially elongated, as at 18, through an arc corresponding to .the angular variation between the most advanced and most retarded ignition required in any particular engine.

\Vithin the cylinder each contact member is circumferentially extended, as at 19, and enlarged in width, and at the farther end has a pin engagement with the end 20 of the longer arm of a small bell crank lever. Each bell crank member is pivotally mounted at 21 on the disk 4, which carries the cylinder 5., and their shorter arms project..as at 22, behind a washer plate 23 which slidably mounted on the outside of the sleeve :3. ()n this washer plate 23 bears a spring which is interposed betweenit and a nut 25 threaded on the end of the sleeve 3, so that the compression of the spring may be adjusted to what is required to balance the centrifugal tendency of the contact numbers under the highest speed of rotation of the shaft 2 acting through the bell crank levers and washer.

It will be noted that the inner weighty portions 19 of the contact members are laterally offset to or from the disk 4 according to their distance from that disk so that hell crank levers of uniform dimensions may be used for all the contacts. While the engine is running, these contact members 19 will, under the influence of centrifugal fozce, move outward about their pivots 15 against the resistance of the spring 24. To enable this outward 'movement to control the timing of the spark of each cylinder in relation to the position of its crank pin, that portion 17 of each contact, which is extended backward from its pivots 15, is concentric with the outer circle of the cylinder 5 when the contact member is in the position corresponding to the minimum rate of speed, the length of the portion 17 being as before explained, of sufficient length to insure an effective closure of the circuit. The circumferential position of the brush 6 in relation to this portion 17 of these contacts is adjusted to make that contact when the crank of that cylinder is in the desired position for ignition at a slow rate of speed. The portion 18 of these contacts, which extends forward of the pivots 15 in the direction of rotation, is curved to a radius which is 'less than that of the outer circle of the cylinder 5, so that as the speed of the engine increases and the members 19 move outward against the resistance of the spring 24 under the influence of centrifugal force, a greater length of the surface 18 will suecessively be brought to the circle of the cylinder 5 until the maximum limit is reached when the whole length of the contact will be exposed to contact with the brush 6. The ignition circuit will thus be closed earlier in its revolution as the speed increases, that is, the ignition will be retarded in relation to the movement of the piston.

In applying the device it will be necessary to arrange the contacts according to the direction of rotation of the shaft 2 in relation to rotation of the engine shaft.

The device is simple in construction and is effective in operation, automatically regulating the time of the ignition of the explosive charge to the speed of the engine so that when the engine is running at a high speed the explosion has time to develop its full force by the time the crank pin is in an effective position to receive it. The advantage of having this done automatically as the speed of the engine varies must result in a more effective engine.

Having now particularly described our invention, we hereby declare that what we claim as new and desire to be protected in by Letters Patent, is:

1.. An automatic spark timer for an internal combustion engine,'comprising the combination with a hollow cylinder of insulating material secured on a shaft which is rotatable with the engine, said cylinder having a circumferentially elongated aperture in it for each ignition circuit of the engine, a metallic contact member in each aperture electrically connected to the engine frame, means cooperative with the speed of rotation for varying circumferentially the length of said contact exposed at the periphery of the cylinder through the aperture, and a brush in electrical connection with the ignition circuit in frictional engagement with the periphery of the cylinder and its contact.

2. An automatic spark timer for an internal combustion engine, said timer compris ing a hollow cylinder of insulating material rotatable with the engine, said cylinder, having a circumferentially elongated aperture in it for each ignition circuit of the engine, a contact member pivotally mounted in each aperture and electrically connected to the engine frame, said contact member having normally a portion of its length coincident with the outer circle of the cylinder, the remainder of its length in the aperture being within the circle of the cylinder but susceptible of moving out to it under an increase in the speed of rotation, and a brush contact for each ignition circuit bearing on the outside of the cylinder and engaging its contact.

3. An automatic spark timer for an internal combustion engine, said timer comprising a hollow cylinder of insulating material secured on a shaft which is rotatable with the engine, said cylinder having a series of circumferentially elongated apertures through it one for each ignit )Il circuit of the engine, said apertures being at equal distances apart and arranged in parallel but different planes of rotation, a contact member pivotally mounted in each aperture and electrically connected to the engine frame, said contact member having a portion rearwardly extended from its pivot which is coincident with the outside of the cylinder at a certain minimum speed of rotation, and a portion forwardly extended from the pivot which forwardly extended portion is inwardly curved from the outer circle-of the cylinder to a radius less than the cylinder.

4. An automatic spark timer for an internal combustion engine, said timer comprising the combination with a hollow cylinder of insulating material rotatable with the engine, said cylinder having a circumfercntially elongated aperture through it for each ignition circuit of the engine, said apertures being angularly equidistant from one another and in adjacent parallel planes of rotation, a contact member pivotally mounted ineach aperture that portion of the contact member aft of the pivot being normally coincident with the outer circle of the cylinder and that portion of it in ad:

Vance of the pivot inclining inward away from that-circle but susceptible of being moved outward under the centrifugal force on the contact member to bring' successive extensions fnom the fulcrumto th circle of the cylinder? under: successive increases of the speed of rotation, a spring counterbalancing the centrifugal effort on the contact member }at different speeds, means for electrically fconnecting the contact member to the engine' frame', and a brush electrically connected to each ignition circuit and hearing on'the cylinder in the plane of each pivctally mounted contact member.

An automatic sparktimer for an internal combustion engine, comprising a cylinder of insulating material secured on a shaft which is rotatable with the engine, a brush connected in each ignition circuit of the engine and bearing on the outer surface of the cylinder, contacts pivotally mounted. in the cylinder under the path of each brush thereon and adapted under centrifugal force with t e brush from the pivot on which it is mounted, and a common spring controlling to vary1 the distance at which contact is made I the outward movement of all the pivotal contact members.

6. An automatic spark timer for, an internal combustion engine, comprising the combination with a shaft rotatable with the engine, of a sleeve secured on the shaft said sleeve having a fiangeprojecting therefrom and supporting a hollow cylinder of insulating material concentric with the shaft, a brush electrically connected to each ignition circuit, said brush in frictional resilient contact with the outside of the cylinder, means for circumferentially varying the position of the brush on the cylinder, a contact member pivotally mounted in an aperture in the cylinder under the path of each brush,

.a portion of which contact member adjacent to the pivot is coincident with the circle of the cylinder in which it is mounted the remainder ofiuch contact member being within the circle at a certain minimum speed of rotation, but susceptible of moving out to the circle at an increased speed of' rotation, and a common spring controlling all the pivotally mounted contact members against the centrifugal force acting on them.

7 An automatic spark timer for internal combustion engines comprising a rotatable hollow cylinder of insulated material hav ing an aperture, a metallic contact member mounted in said aperture, speed controlled means for projecting said contact member through said aperture to vary the exposed circumferential length of the same at the periphery of the cylinder, and a contact brush adapted to engage said cylinder and said cylinder contact, said brush being adapted for connection to one terminal of the ignition circuit and said cylinder contact adapted for connection to the other terminal of the ignition circuit.

In testimony whereof we aflix our signatures in presence of two witnesses.

GEORGE R. WRIGHT. FREDRICK W. JOHNSON. Witnesses:

ROWLAND BRITTAIN, MAY VVHYTE.

Copies 0t this patent may be obtained for five cents each, by addressing the "Commissioner of Patents,

' Washington, D. C. 

